Copy a Length

Constructing one segment to be the same length as another segment is different from just copying the segment. Euclid used circles to construct a segment that was the same length as another segment, but located at a different endpoint. That was a complicated procedure. In GeoGebra, we can use the compass tool to make that construction easier.
After Euclid did his construction of an equilateral triangle, he used that to show how to copy a segment length to another location. In dynamic geometry, this means making the length of a second segment (CH) dependent on the length of the first segment (AB).